////////////////////////////////////////////////////////////////////////////////
// Filename: positioncolorshader.cpp
////////////////////////////////////////////////////////////////////////////////
#include "positioncolorshader.hpp"

miv::PositionColorShader::PositionColorShader() {
	m_vertexShader = NULL;
	m_pixelShader = NULL;
	m_layout = NULL;
	m_matrixBuffer = NULL;
}

miv::PositionColorShader::~PositionColorShader() {

}

bool miv::PositionColorShader::Initialize(ID3D11Device* device, HWND hWnd) {
	bool result;

	result = InitializeShader(device, hWnd, L"../Mark-IV-Engine/trunk/src/core/graphics/shaders/positioncolor.vs",
			L"../Mark-IV-Engine/trunk/src/core/graphics/shaders/positioncolor.ps");
	if (!result) {
		return false;
	}

	return true;
}

void miv::PositionColorShader::Shutdown() {
	ShutdownShader();
}

bool miv::PositionColorShader::Render(ID3D11DeviceContext* deviceContext, int indexCount,
		D3DXMATRIX worldMatrix, D3DXMATRIX viewMatrix, D3DXMATRIX projectionMatrix) {
	bool result;

	result = SetShaderParameters(deviceContext, worldMatrix, viewMatrix, projectionMatrix);
	if (!result) {
		return false;
	}

	RenderShader(deviceContext, indexCount);

	return true;
}

bool miv::PositionColorShader::InitializeShader(ID3D11Device* device, HWND hWnd,
		WCHAR* vsFilename, WCHAR* psFilename) {
	HRESULT result;
	ID3D10Blob* errorMessage;
	ID3D10Blob* vertexShaderBuffer;
	ID3D10Blob* pixelShaderBuffer;
	D3D11_INPUT_ELEMENT_DESC polygonLayout[2];
	unsigned int numElements;
	D3D11_BUFFER_DESC matrixBufferDesc;

	errorMessage = NULL;
	vertexShaderBuffer = NULL;
	pixelShaderBuffer = NULL;

	result = D3DX11CompileFromFileW(vsFilename, NULL, NULL, "PositionColorVertexShader", "vs_5_0", D3D10_SHADER_ENABLE_STRICTNESS,
			0, NULL, &vertexShaderBuffer, &errorMessage, NULL);
	if (FAILED(result)) {
		if (errorMessage) {
			OutputShaderErrorMessage(errorMessage, hWnd, vsFilename);
		} else {
			MessageBoxW(hWnd, vsFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

	result = D3DX11CompileFromFileW(psFilename, NULL, NULL, "PositionColorPixelShader", "ps_5_0", D3D10_SHADER_ENABLE_STRICTNESS,
			0, NULL, &pixelShaderBuffer, &errorMessage, NULL);
	if (FAILED(result)) {
		if (errorMessage) {
			OutputShaderErrorMessage(errorMessage, hWnd, psFilename);
		} else {
			MessageBoxW(hWnd, psFilename, L"Missing Shader File", MB_OK);
		}

		return false;
	}

	// Create the vertex shader from the buffer.
	result = device->CreateVertexShader(vertexShaderBuffer->GetBufferPointer(), vertexShaderBuffer->GetBufferSize(), NULL, &m_vertexShader);
	if(FAILED(result))
	{
		return false;
	}

	// Create the pixel shader from the buffer.
	result = device->CreatePixelShader(pixelShaderBuffer->GetBufferPointer(), pixelShaderBuffer->GetBufferSize(), NULL, &m_pixelShader);
	if(FAILED(result))
	{
		return false;
	}

	// Now setup the layout of the data that goes into the shader.
	// This setup needs to match the VertexType stucture in the ModelClass and in the shader.
	polygonLayout[0].SemanticName = "POSITION";
	polygonLayout[0].SemanticIndex = 0;
	polygonLayout[0].Format = DXGI_FORMAT_R32G32B32_FLOAT;
	polygonLayout[0].InputSlot = 0;
	polygonLayout[0].AlignedByteOffset = 0;
	polygonLayout[0].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[0].InstanceDataStepRate = 0;

	polygonLayout[1].SemanticName = "COLOR";
	polygonLayout[1].SemanticIndex = 0;
	polygonLayout[1].Format = DXGI_FORMAT_R32G32B32A32_FLOAT;
	polygonLayout[1].InputSlot = 0;
	polygonLayout[1].AlignedByteOffset = D3D11_APPEND_ALIGNED_ELEMENT;
	polygonLayout[1].InputSlotClass = D3D11_INPUT_PER_VERTEX_DATA;
	polygonLayout[1].InstanceDataStepRate = 0;

	// Get a count of the elements in the layout.
	numElements = sizeof(polygonLayout) / sizeof(polygonLayout[0]);

	// Create the vertex input layout.
	result = device->CreateInputLayout(polygonLayout, numElements, vertexShaderBuffer->GetBufferPointer(),
					   vertexShaderBuffer->GetBufferSize(), &m_layout);
	if(FAILED(result))
	{
		return false;
	}

	// Release the vertex shader buffer and pixel shader buffer since they are no longer needed.
	vertexShaderBuffer->Release();
	vertexShaderBuffer = 0;

	pixelShaderBuffer->Release();
	pixelShaderBuffer = 0;

	// Setup the description of the dynamic matrix constant buffer that is in the vertex shader.
	matrixBufferDesc.Usage = D3D11_USAGE_DYNAMIC;
	matrixBufferDesc.ByteWidth = sizeof(MatrixBufferType);
	matrixBufferDesc.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
	matrixBufferDesc.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
	matrixBufferDesc.MiscFlags = 0;
	matrixBufferDesc.StructureByteStride = 0;

	// Create the constant buffer pointer so we can access the vertex shader constant buffer from within this class.
	result = device->CreateBuffer(&matrixBufferDesc, NULL, &m_matrixBuffer);
	if(FAILED(result))
	{
		return false;
	}

	return true;
}

void miv::PositionColorShader::ShutdownShader()
{
	// Release the matrix constant buffer.
	if(m_matrixBuffer)
	{
		m_matrixBuffer->Release();
		m_matrixBuffer = 0;
	}

	// Release the layout.
	if(m_layout)
	{
		m_layout->Release();
		m_layout = 0;
	}

	// Release the pixel shader.
	if(m_pixelShader)
	{
		m_pixelShader->Release();
		m_pixelShader = 0;
	}

	// Release the vertex shader.
	if(m_vertexShader)
	{
		m_vertexShader->Release();
		m_vertexShader = 0;
	}
}

void miv::PositionColorShader::OutputShaderErrorMessage(ID3D10Blob* errorMessage, HWND hWnd, WCHAR* shaderFilename)
{
	char* compileErrors;
	unsigned long bufferSize, i;
	std::ofstream fout;


	// Get a pointer to the error message text buffer.
	compileErrors = (char*)(errorMessage->GetBufferPointer());

	// Get the length of the message.
	bufferSize = errorMessage->GetBufferSize();

	// Open a file to write the error message to.
	fout.open("shader-error.txt");

	// Write out the error message.
	for(i=0; i<bufferSize; i++)
	{
		fout << compileErrors[i];
	}

	// Close the file.
	fout.close();

	// Release the error message.
	errorMessage->Release();
	errorMessage = 0;

	// Pop a message up on the screen to notify the user to check the text file for compile errors.
	MessageBoxW(hWnd, L"Error compiling shader.  Check shader-error.txt for message.", shaderFilename, MB_OK);
}

bool miv::PositionColorShader::SetShaderParameters(ID3D11DeviceContext* deviceContext, D3DXMATRIX worldMatrix,
					   D3DXMATRIX viewMatrix, D3DXMATRIX projectionMatrix)
{
	HRESULT result;
	D3D11_MAPPED_SUBRESOURCE mappedResource;
	MatrixBufferType* dataPtr;
	unsigned int bufferNumber;

	// Transpose the matrices to prepare them for the shader.
	D3DXMatrixTranspose(&worldMatrix, &worldMatrix);
	D3DXMatrixTranspose(&viewMatrix, &viewMatrix);
	D3DXMatrixTranspose(&projectionMatrix, &projectionMatrix);

	// Lock the constant buffer so it can be written to.
	result = deviceContext->Map(m_matrixBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
	if(FAILED(result))
	{
		return false;
	}

	// Get a pointer to the data in the constant buffer.
	dataPtr = (MatrixBufferType*)mappedResource.pData;

	// Copy the matrices into the constant buffer.
	dataPtr->world = worldMatrix;
	dataPtr->view = viewMatrix;
	dataPtr->projection = projectionMatrix;

	// Unlock the constant buffer.
	deviceContext->Unmap(m_matrixBuffer, 0);

	// Set the position of the constant buffer in the vertex shader.
	bufferNumber = 0;

	// Finanly set the constant buffer in the vertex shader with the updated values.
	deviceContext->VSSetConstantBuffers(bufferNumber, 1, &m_matrixBuffer);

	return true;
}

void miv::PositionColorShader::RenderShader(ID3D11DeviceContext* deviceContext, int indexCount)
{
	// Set the vertex input layout.
	deviceContext->IASetInputLayout(m_layout);

	// Set the vertex and pixel shaders that will be used to render this triangle.
	deviceContext->VSSetShader(m_vertexShader, NULL, 0);
	deviceContext->PSSetShader(m_pixelShader, NULL, 0);

	// Render the triangle.
	deviceContext->DrawIndexed(indexCount, 0, 0);

	return;
}
